Don't buy cotton swim trunks.

Cotton soaks up water like a sponge and clings to everything. You want polyester, nylon, or a quick-dry blend — those fabrics shed water and stay light.

The second thing is fit. Too loose and they balloon in the water; too tight and they act like compression shorts. Look for something with a mesh liner (most do) and a drawstring that actually ties tight. Side vents help with drainage too.

Brand doesn’t matter much. Target, Amazon, or a decent sportswear line — they all use the same synthetics. Just check the tag: 100% polyester or nylon, maybe with spandex for stretch.

A good test: if the fabric feels dry compared to a cotton t-shirt when you wet it, you’re good.